1. Field of the Invention
The invention relates to a pneumatic nail driving device, more particularly to a barrel unit with a removable cover plate for a pneumatic nail driving device.
2. Description of the Related Art
In a known pneumatic nail driving device, a nail feeding unit aligns a nail from a nail cartridge with a nail impelling unit so as to discharge the nail via a barrel unit. Jamming of the pneumatic nail driving device usually occurs, thereby preventing the discharge of the nail through the barrel unit. In order to resume proper operation of the pneumatic nail driving device, a cover plate of the barrel unit is removed to remedy the cause of jamming. Thus, it is important for the barrel unit to have a structure which facilitates installation and removal of the cover plate.
Referring to FIGS. 1 and 2, a conventional barrel unit is shown to be installed on a front end of a pneumatic nail driving device 1 and includes an elongated base plate 2 which extends forwardly from the housing of the pneumatic nail driving device 1. The base plate 2 has a top face formed with a longitudinal discharge groove and a pair of upwardly extending hooking lugs 201 which are disposed respectively on opposite sides of the discharge groove and which are located at a front portion of the base plate 2, and a pair of upwardly extending first pivot ears 202 which are disposed respectively on opposite sides of the discharge groove and which are located at a rear portion of the base plate 2. An elongated cover plate 3 is superimposed on the base plate 2, and has a pivot end 300 pivoted to the first pivot ears 202 of the baseplate 2, and a pair of upwardly extending second pivot ears 301 between the pivot end 300 and the hooking lugs 201. A latch includes an operating lever 311 formed with a pair of third pivot ears 311" mounted pivotally on the second pivot ears 301 of the cover plate 30, and a U-shaped clasper 312 secured to the operating lever 311.
After the clasper 312 has been disposed around the hooking lugs 201, the operating lever 311 is turned rearwardly so as to pull the clasper 312 to engage tightly the hooking lugs 201 and so as to press the cover plate 3 against the base plate 2. When it is desired to remove the cover plate 3, the operating lever 311 is turned forwardly to permit removal of the clasper 312 from the hooking lugs 201 and to permit lifting of the cover plate 3 from the base plate 2.
If the pneumatic nail driving device 1 is used to drive several nails in rapid succession, the shock experienced by the cover plate 3 during the nail driving operation may loosen the operating lever 311 in the arrow directions (X,Y), as best shown in FIG. 2, thereby resulting in untimely removal of the cover plate 3 from the base plate 2.